UC San Diego

Part 1: Development and validation of an analytical method by liquid chromatography-tandem mass spectrometry to detect putrescine, cadaverine, spermidine, spermine, n8-acetylspermidine, and n1-acetylspermine as benzyl amide derivatives in biological samples were completed. The derivatization conditions were optimized for all PAs, and method validation was completed for putrescine (PUT) and spermidine (SPD) using isotope dilution techniques. The method exhibited: high accuracy (<±15% error) and precision (<±10% RSD); product stability of >22 days; linearity within concentration range of 0.40-50 ng/mL for PUT and 0.42-530 ng/mL for SPD; level of detection (LOD) of 2.8 and 2.4 picograms (pg); and level of quantitation (LOQ) of 20 and 21 pg for PUT and SPD, respectively. Matrix effects and interferences were shown to not affect accuracy. The method developed provided superior with shorter analysis time than other published methods. Levels of PUT and SPD were determined to be 5.75 ± 0.1 and 43.8 ± 1 ng/mL, respectively in a sample as small as 4 fruit flies.

Part 2: This project was a proof of concept study that used breath component analysis (BCA) to determine if a unique volatile organic compound (VOC) could be measured in human breath 72 hours or longer following a brief exposure. A portable breathing mask with a pressurized canister was constructed to provide 1-2 ppm exposures of the tracer chemicals to the subjects. An EBC sample collection device and canister cleaning system were modified to provide clean sample blanks. Analytical protocols were established to collect BCA from subjects using canisters and adsorbent traps. The chemicals tested and the maximum duration they were detectable in a subjects’ breath (days) were methoxyflurane (1.2), enflurane (7.7), sevoflurane (1.2), α,α,α-trifluorotoluene (14), 4-chlorobenzotrifluoride (7.2), and 3-fluorobenzotrifluoride (1.2). The rate constants for the most promising candidate chemicals followed a one-compartment (first order kinetics) model. Other compounds of similar chemical properties are potential candidates for further study. The applications of this proof of concept study may lead to the development of tools for use in toxicology, forensics, and security.